The present invention relates to drums, and more particularly to drums whose pitch is adjustable by rotation of the drum shell and/or activation of a pedal connected to drumhead-tensioning apparatus.
It is well known in the art to adjust the pitch of a drum by varying the tension on the drumhead. Devices for achieving this function have typically been used in conjunction with tympani, and have consisted of assemblies whereby activation of a pedal stretches the drumhead to increase the pitch. Tympani are also known which are adjustable in pitch by rotation of the drum shell about a central support axis. While combined pitch adjustability by rotation as well as by a pedal arrangement has been found in the prior art, the pedal-adjustable feature of such drums has typically required a large, heavy, cumbersome apparatus which is not separable from the drum itself. Also, the height of such drums above the floor or other surface has not been readily adjustable.
Another type of drum whose pitch may be varied by rotation is a drum which has been manufactured and sold for a number of years by the assignee of the present application under the trademark "RotoTom". A "RotoTom" drum has a drumhead stretched over an upper die casting or "spider" and held by a counter hoop. The upper die casting has a central hub against which abuts a threaded shaft. Threaded upon the threaded shaft is a lower die casting or spider rigidly affixed to the counter hoop. Rotation of the lower die casting about the threaded shaft causes the force exerted on the drumhead by the upper die casting to vary, thus changing the pitch of the RotoTom drum.
No means has yet been made commercially available for adjusting the pitch of a RotoTom drum by means of a pedal. It has been suggested to design a pedal-adjustable RotoTom drum by drilling the central shaft of the drum and inserting a push rod therethrough, the push rod to be activated by a pedal attached to a cable. Such a design is described in the application of Robert J. Henrit, Ser. No. 67,737 filed concurrently herewith and assigned to the assignee of the present application. However, such an arrangement cannot be easily retrofitted to existing RotoTom drums, because of the necessity of drilling the central shaft of the drum. Also, the suggested design makes no provision for locking the pedal or for convenient height adjustability.